
reflectivity well below 1%) causes amplified spontaneous emission (ASE) and
external FBG frequency stabilization issues.
Thus, for long cavities, constant power ratio scaling is favored with the follow-
ing scaling rules:
RðLÞ¼RðL
0
Þ
GðLÞ¼
L
0
L
GðL
0
Þ;ðLÞ¼
L
0
L
ðL
0
Þ
As a consequence of keeping the power ratio constant, the mirror reflectivity is
also constant; therefore, this method is often called constant mirror reflectivity
scaling. Requirements on confinement and optical losses are demanding. Both have
to be reduced linearly with increased cavity length. The constant mirror reflectivity
scaling has the advantage of making, to zeroth order, average